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Brake squeal noise is a top warranty concernsmplaints for virtually all automotive companies. How to identify squeal frequencies and mode shapes is typically very challenging. The identification of potential squeal problems still rely heavily on experimental methods using inertia and chassis dynamometers or on-road tests, but these require hardware to run. Good numerical methods have advantages of evaluating up-front designs before the cutting tools ever hit any metal. But for brake squeal, there are still many challenges to overcome to correctly model a complete brake system due to the nature of the complexity of the frictional excitation. In this paper, a disc brake system model was established to simulate brake squeal using nonlinear transient analysis methods provided through LS-DYNA. The model includes rotor, pads, linings, caliper and pistons. From the example analyzed, the squeal frequency is identified using frequency domain analysis of the numerical time-domain output.

The objective of this paper is to develop a test capable of ranking lift-gates based on strain concentration levels reflected in fringe characteristics in the known stress/strain concentration and fracture vicinity. First, the system (lift gate glass, adhesive and appliqué) is chosen as test sample since the subsystem (local appliqué) does not exhibit the failure mode observed in the field test. Subsequently, it has been identified that the thermal component (rather than mechanical) is the predominant load by laser scanning vibrometry and confirmed via field test data. Next, digital shearography has been selected as the measurement and visualization tool of strain distribution due to its various advantages such as full field view and non-contact advantages. Finally, the test method has been applied to rank and optimize the structural configuration around appliqués' to reduce / eliminate failure.